MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: hazem on May 28, 2020, 05:17:20 pm

Title: block 32 fuel trim
Post by: hazem on May 28, 2020, 05:17:20 pm

Hi Dears,

I'm writing looking for help to sort my car's problem out. it is Mk5 gti edition 30 with byd 2.0t engine.

Now everything seems to be ok with it, except fuel trim 32. it is around 12-16%.

What i notice from a daily checking is that when i drive on motorway for steady speed like 100-120 km/hour it decreases to be 10-12%, but driving in traffic jam it jumps up to be 14-16% and may be 17% sometimes!!

Mpg is awful as it goes around 15!

I checked out all possible vacuum leaks like PCV, Evap purge valve etc but everything seems ok.
Injectors, dv, oxygen sensors, maf all are replaced with brand new ones!

Also it doesn't has any fault codes! So what do you think about this!

Thanks,
Hazem

Title: Re: block 32 fuel trim
Post by: bacillus on May 28, 2020, 05:24:43 pm

What intake have you got installed?

Title: Re: block 32 fuel trim
Post by: hazem on May 28, 2020, 05:31:42 pm

Stock one

Title: Re: block 32 fuel trim
Post by: ROH ECHT on May 29, 2020, 06:21:25 pm

Could just be a worn engine...this is common.
But more often it is due to a leak in air inlet system or EVAP system....or a failing N80 EVAP purge.

Title: Re: block 32 fuel trim
Post by: pudding on May 29, 2020, 09:11:21 pm

Could be a dead MAF.  Check for around 2.4g/s at a hot idle with some fluctuation.  If the reading is a fixed value and doesn't move, that's a good sign the MAF has had it.  Either that or you have a serious air leak downstream of the MAF.  Split turbo inlet hose perhaps.  15mpg and 12-16% long term trims is MASSIVELY off spec for stock hardware.

Title: Re: block 32 fuel trim
Post by: hazem on May 30, 2020, 02:37:48 am

Thanks Guys, much appreciated
Maf is good, the main suspect now goes to N80 valve considering two facts, first that LTFT decreases after a long drive with steady speed, it jumps for 14-16 in traffic jam. The second fact is that the only fault code i had once in awhile is p0441 which from what i understand means a leak in the eavp or faulty n80 valve.
So am I thinking the right way or what?

Title: Re: block 32 fuel trim
Post by: ROH ECHT on May 30, 2020, 05:09:51 am

You can test the intake side of the N80 with a gauged vacuum pump or just replace the N80 because it is not expensive. But you should do your best to inspect for leaks all along the intake/boost, brake booster, and EVAP tubing and hoses.

If you choose to test the N80 with a vacuum pump, give it more than 15 inHg. It should not drop or bleed back to atmospheric pressure. If it, the needle, drops back to zero...replace the N80.